The ocean floor (Bruce Heezen Commemorative Volume), edited by R. A. Scrutton and M. Talwani,Wiley, Chichester, 1982. No. of pages: 318. Price: £47.50; US$99     

N. H. Kenyon 《Geological Journal》1984,19(1):83-83

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Continental margin sedimentation, with special reference to the north-east Atlantic margin   总被引：7，自引：0，他引：7  

Philip P. E. Weaver  Russell B. Wynn  Neil H. Kenyon  Jeremy Evans 《Sedimentology》2000,47(S1):239-256

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Late Quaternary fire regimes of Australasia     

S.D. Mooney  S.P. Harrison  P.J. Bartlein  A.-L. Daniau  J. Stevenson  K.C. Brownlie  S. Buckman  M. Cupper  J. Luly  M. Black  E. Colhoun  D. D’Costa  J. Dodson  S. Haberle  G.S. Hope  P. Kershaw  C. Kenyon  M. McKenzie  N. Williams 《Quaternary Science Reviews》2011,30(1-2):28-46

We have compiled 223 sedimentary charcoal records from Australasia in order to examine the temporal and spatial variability of fire regimes during the Late Quaternary. While some of these records cover more than a full glacial cycle, here we focus on the last 70,000 years when the number of individual records in the compilation allows more robust conclusions. On orbital time scales, fire in Australasia predominantly reflects climate, with colder periods characterized by less and warmer intervals by more biomass burning. The composite record for the region also shows considerable millennial-scale variability during the last glacial interval (73.5–14.7 ka). Within the limits of the dating uncertainties of individual records, the variability shown by the composite charcoal record is more similar to the form, number and timing of Dansgaard–Oeschger cycles as observed in Greenland ice cores than to the variability expressed in the Antarctic ice-core record. The composite charcoal record suggests increased biomass burning in the Australasian region during Greenland Interstadials and reduced burning during Greenland Stadials. Millennial-scale variability is characteristic of the composite record of the sub-tropical high pressure belt during the past 21 ka, but the tropics show a somewhat simpler pattern of variability with major peaks in biomass burning around 15 ka and 8 ka. There is no distinct change in fire regime corresponding to the arrival of humans in Australia at 50 ± 10 ka and no correlation between archaeological evidence of increased human activity during the past 40 ka and the history of biomass burning. However, changes in biomass burning in the last 200 years may have been exacerbated or influenced by humans.  相似文献   

A deep IZ survey of 1.1 deg² of the Pleiades cluster: three candidate members with  M < 0.04 M_⊙      

P. D. Dobbie  F. Kenyon  R. F. Jameson  S. T. Hodgkin  D. J. Pinfield  S. L. Osborne 《Monthly notices of the Royal Astronomical Society》2002,335(3):687-697

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Turbidites around an active fault scarp on the Lower Valencia Fan, northwest Mediterranean     

S. A. Morris  J. Alexander  N. H. Kenyon  A. F. Limonov 《Geo-Marine Letters》1998,18(2):165-171

 Side-scan sonar images from the Lower Valencia Fan show that turbidite bedforms (chevrons) and net sediment aggradation vary around a small fault scarp. One or more turbidity currents were affected by the fault, but the exact timing of the fault movement in relation to the chevrons is not known. A scaled laboratory experiment showed that mean flow vector would not be affected by a current flowing over an obstacle of similar height to flow depth ratio.  相似文献   

Deep-water sediment wave fields, bottom current sand channels and gravity flow channel-lobe systems: Gulf of Cadiz, NE Atlantic   总被引：4，自引：0，他引：4  

Edward L. Habgood  Neil H. Kenyon  Douglas G. Masson  rey Akhmetzhanov  Philip P. E. Weaver  Joan Gardner†  Thierry Mulder‡ 《Sedimentology》2003,50(3):483-510

Abstract A study of the seafloor of the Gulf of Cadiz west of the Strait of Gibraltar, using an integrated geophysical and sedimentological data set, gives new insights into sediment deposition from downslope thermohaline bottom currents. In this area, the Mediterranean Outflow (MO) begins to mix with North Atlantic waters and separates into alongslope geostrophic and downslope ageostrophic components. Changes in bedform morphology across the study area indicate a decrease in the peak velocity of the MO from >1 m s^?1 to <0·5 m s^?1. The associated sediment waves form a continuum from sand waves to muddy sand waves to mud waves. A series of downslope‐oriented channels, formed by the MO, are found where the MO starts to descend the continental slope at a water depth of ≈700 m. These channels are up to 40 km long, have gradients of <0·5°, a fairly constant width of ≈2 km and a depth of ≈75 m. Sand waves move down the channels that have mud wave‐covered levees similar to those seen in turbidite channel–levee systems, although the channel size and levee thickness do not decrease downslope as in typical turbidite channel systems. The channels terminate abruptly where the MO lifts off the seafloor. Gravity flow channels with lobes on the basin floor exist downslope from several of the bottom current channels. Each gravity flow system has a narrow, slightly sinuous channel, up to 20 m deep, feeding a depositional lobe up to 7 km long. Cores from the lobes recovered up to 8·5 m of massive, well‐sorted, fine sand, with occasional mud clasts. This work provides an insight into the complex facies patterns associated with strong bottom currents and highlights key differences between bottom current and gravity flow channel–levee systems. The distribution of sand within these systems is of particular interest, with applications in understanding the architecture of hydrocarbon reservoirs formed in continental slope settings.  相似文献   

Upwelling by a wave pump     

Kern E. Kenyon 《Journal of Oceanography》2007,63(2):327-331

A rigid open-ended pipe is submerged in the ocean below the troughs of the surface waves and held fixed in the vertical position, the lower end being at or below the depth of wave influence. When surface gravity waves propagate past the pipe, water flows up as long as waves are present. The steady upward vertical velocity in the center of the pipe is calculated to be proportional to the square of both the average wave steepness and the pipe’s radius. An application is to bring nutrient rich waters up into the sunlit surface layers of the open oceans.  相似文献   

Shoaling waves: A discussion     

Kern E. Kenyon 《Journal of Oceanography》2006,62(6):923-927

Surface gravity waves are commonly observed to slow down and to stop at a beach without any noticeable reflection taking place. We assume that as a consequence the waves are continuously giving up their linear and angular momenta, which they carry with them, along with energy, as they propagate into gradually decreasing mean depths of water. It takes a force to cause a time rate of decrease in the linear momentum and a torque to produce a time rate of decrease in the angular momentum. Both a force and a torque operate on the shoaling waves, due to the presence of the sloping bottom, to cause the diminution of their linear and angular momenta. By Newton’s third law, action equals reaction, an equal but opposite force and torque are exerted on the bottom. No other mechanisms for transferring linear and angular momenta are included in the model. Since the force on the waves acts over a horizontal distance during shoaling, work is done on the waves and energy flux is not conserved. Bottom friction, wave interaction with a mean flow, scattering from small-scale bottom irregularities and set-up are neglected. Mass flux is conserved, which leads to a shoreward monotonic decrease in amplitude consistent with available swell data. The formula for the time-independent force on the bottom agrees qualitatively with observations in seven different ways: four for swell attenuation and three for sediment transport on beaches. Ardhuin (2006) argues against a mean force on the bottom that is not hydrostatic, mainly by using conservation of energy flux. He also applies the action balance equation to shoaling waves. Action is a difficult concept to grasp for motion in a continuum; it cannot be easily visualized, and it is not really necessary for solving the shoaling wave problem. We prefer angular momentum because it is clearly related to the observed orbital motion of the fluid particles in progressive surface waves. The physical significance of wave action for surface waves has been described recently by showing that in deep water action is equivalent to the magnitude of the wave’s orbital angular momentum (Kenyon and Sheres, 1996). Finally, Ardhuin requires that there be a significant exchange of linear momentum between shoaling waves and an unspecified mean flow, although the magnitude and direction of the exchange are not predicted. No mention is made of what happens to the orbital angular momentum during shoaling. Mass flux conservation is not stated.  相似文献   

Channel systems and lobe construction in the Mississippi Fan     

Louis E. Garrison  Neil H. Kenyon  Arnold H. Bouma 《Geo-Marine Letters》1982,2(1-2):31-39

Morphological features on the Mississippi Fan in the eastern Gulf of Mexico were mapped using GLORIA II, a long-range side-scan sonar system. Prominent is a sinuous channel flanked by well-developed levees and occasional crevasse splays. The channel follows the axis and thickest part of the youngest fan lobe; seismic-reflection profiles offer evidence that its course has remained essentially constant throughout lobe development. Local modification and possible erosion of levees by currents indicates a present state of inactivity. Superficial sliding has affected part of the fan lobe, but does not appear to have been a factor in lobe construction.  相似文献   

Introduction: marine geoscience research by the UNESCO-IOC Training-through-Research program in the Mediterranean and Black seas     

N. H. Kenyon 《Geo-Marine Letters》1998,18(2):79-80

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